In faucets, cartridge assemblies are installed in valve bodies. Rotation of a cartridge assembly within a valve body can damage the faucet and even render the faucet inoperable. In order to resist rotation of the cartridge assembly within the valve body, the cartridge assembly can include a key and the valve body can include a corresponding keyway. Prior keys and keyways include a center line that intersects a central longitudinal axis of the cartridge assembly.